Added new effect to build up the stairs (with or without an image overlay) using a scanline. Fixed issue with calibration: trying to indicate a point in a viewport of projector B using the cursor projected by A doesn't work.. Now, when trying to calibrate in a certain projectorview, and the mouse isn't in that view, its background is set to red. Implementation not perfect, but works. First tried to set the mouse cursor, but it turned out that this can only be done in WM_SETCURSOR and OF doesn't seem to have an (easy) entry point for that, so that code can be removed).